Bug 1967166

Summary:	Compile libguestfs with ./configure --enable-appliance-format-auto to allow for qcow2-format fixed appliances
Product:	[Fedora] Fedora	Reporter:	Alice Frosi <afrosi>
Component:	libguestfs	Assignee:	Richard W.M. Jones <rjones>
Status:	CLOSED ERRATA	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	34	CC:	berrange, rjones
Target Milestone:	---
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:	libguestfs-1.45.6-4.fc34	Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:
Clones:	2025944 (view as bug list)		Environment:
Last Closed:	2021-06-19 01:08:09 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	2025944

Description Alice Frosi 2021-06-02 14:27:37 UTC

Description of problem:
Kubevirt plans to integrate libguestfs. The build setup uses bazel to build the container images, and this requires a fixed appliance. The appliance is extracted and copy into the container image layer. The root filesystem is a sparse file, and it makes the image size very large 5.59GB. A better option would be to use qcow2 format for the root. However, the current libguestfs explicitly set raw for the root. It will be very useful to have a way to be able to use qcow2 format for the root filesystem 


Version-Release number of selected component (if applicable):
libguestfs 1.44


How reproducible:
Always

Steps to Reproduce:
1. Extract the libguestfs appliance 
2. Build a container image with the extracted appliance
3. Verify the image size

Additional info:
The original problem can be found at https://github.com/kubevirt/kubevirt/pull/5402

Comment 1 Richard W.M. Jones 2021-06-03 09:30:48 UTC

The request here is to use the build option:

  ./configure --enable-appliance-format-auto

This changes the way libguestfs opens the appliance by not forcing the
root disk to be in raw format.  The exact changes are:

https://github.com/libguestfs/libguestfs/blob/e68a844eb406f0b32cc2c4e60ca66bc1a7f94bdc/lib/launch-direct.c#L641

https://github.com/libguestfs/libguestfs/blob/e68a844eb406f0b32cc2c4e60ca66bc1a7f94bdc/lib/launch-libvirt.c#L497

Because we don't force raw format, this makes it possible to construct
a qcow2-based fixed appliance, which works around the problems that
containers have preserving sparseness.  For libguestfs in Fedora we
will of course continue to use a supermin-built appliance in raw format.

I wanted to see if this would have any overhead on the ordinary (raw) case.
On my own system, without the option:

$ ./run hyperfine -w 3 'guestfish -a /dev/null run'
Benchmark #1: guestfish -a /dev/null run
  Time (mean ± σ):      1.601 s ±  0.015 s    [User: 18.3 ms, System: 19.6 ms]
  Range (min … max):    1.580 s …  1.625 s    10 runs

With the option:

$ ./run hyperfine -w 3 'guestfish -a /dev/null run'
Benchmark #1: guestfish -a /dev/null run
  Time (mean ± σ):      1.596 s ±  0.023 s    [User: 16.5 ms, System: 21.3 ms]
  Range (min … max):    1.570 s …  1.647 s    10 runs

This is well within error bars so I'm not worried from that point of view.

Comment 2 Fedora Update System 2021-06-03 13:58:35 UTC

FEDORA-2021-a937a48cdd has been submitted as an update to Fedora 34. https://bodhi.fedoraproject.org/updates/FEDORA-2021-a937a48cdd

Comment 3 Fedora Update System 2021-06-04 01:19:06 UTC

FEDORA-2021-a937a48cdd has been pushed to the Fedora 34 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --advisory=FEDORA-2021-a937a48cdd`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2021-a937a48cdd

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 4 Fedora Update System 2021-06-19 01:08:09 UTC

FEDORA-2021-a937a48cdd has been pushed to the Fedora 34 stable repository.
If problem still persists, please make note of it in this bug report.